The present invention relates generally to chucks for use with drills or with electric or pneumatic power drivers. Both hand and electric or pneumatic power tool drivers are well known. Any number of conventional tools are used with such drivers, such as drill bits, screw drivers, nut drivers, burrs, grinding stones, and other cutting or abrading tools. The power drivers are conventionally configured with a chuck which is adjustable over a relatively wide range to hold the tools to a rotatable spindle of the power drivers. The chuck can be attached to the drivers by a conventional threaded or tapered bore, or other conventional attaching mechanisms.
A wide variety of chucks have been developed in the art. In one form of chuck, three jaws spaced circumferentially, approximately 120.degree. apart from each other, are constrained by angularly disposed passageways in a body attached onto the drive spindle and configured so that rotation of the body in one direction relative to a constrained nut engaging the jaws forces the jaws into gripping relationship with respect to the shank of a tool bit, while rotation in the opposite direction releases the gripping relationship Such a chuck may be keyless if it is rotated by hand. Such keyless chucks are well known to those skilled in the art. The jaws engage with the drive nut by way of threads having the same pitch for all of the jaws. In this manner, the jaws advance the same degree upon rotation of the nut. However it is important that the jaws move longitudinally so that in their fullest extended position, the jaws have the same longitudinal length and meet at the axis of the tool bore defined in the chuck body. For this reason, with conventional multi-threaded jaws, the threads are sequentially and variably off-set from ends of the jaw blades to account for the circumferential spacing of the jaws and to ensure that the jaws meet at the axis of the chuck in their fully extended position. Thus, the jaws are not interchangeable in a conventional chuck and it is extremely important that the jaws are placed in the right order within the chuck during the manufacturing and assembly process. This requires a tedious and time consuming process. If the jaws are not placed in the correct order, the chuck does not function correctly and must be disassembled and reassembled in the proper order.
With conventional chucks, the body member is typically formed from metal bar stock and the jaw passageways are machined through the bar stock. The machine process thus requires that the passageways be essentially circular and uniform in cross section. The jaw blades have a correspondingly shaped profile and are generally not distinguishable from each other except for the off-set in jaw threads.